Just trying to get started with SketchUp Web. So, reading the Help Centre for under “Creating and Editing Models” heading, it says:
To create a new model in SketchUp for Web, you start with a template. Follow these steps:
*1. In SketchUp for Web, click the Open Model/Preferences icon * 2. On the panel that appears, click the New Model icon . The following figure shows your template options. 3. Select a template that reflects your desired units of measure. Your options include feet and inches, meters, or millimeters. After you click an option, your new model opens in SketchUp for Web, ready for you to begin 3D-modeling.
Say if you have chosen millimeters (something you can still change at any time), you just start modeling. As you go along you can change any settings the way you like them to be. At the end you save your model with these settings. Just start drawing stuf with the ‘Line’ tool. Make a few mistakes, no harm done. If you don’t start you won’t get anywhere with SketchUp.
That little man is to give you a sense of scale, the size you are drawing. Best if you model real size (scale 1:1 so to speak). You cannot set scale in SketchUp. You can however model things in a different scale. But that is (most of the time) pointless